The present invention relates to the art of interactive image-guided surgery and interactive surgical procedures which require patient breath holding or breathing control. It finds particular application in conjunction with planning and implementation stages of minimally invasive stereotactic surgical procedures performed in CT imaging systems using a localization device to orient surgical tools such as biopsy or brachytherapy needles or the like for tissue sampling or planning or placement of objects or instruments within the body of a patient, and will be described with particular reference thereto. It is to be appreciated, however, that the invention is also applicable to a wide range of imaging equipment and techniques, for example ultrasonic and magnetic resonance imaging devices, and to a broad range of minimally invasive surgical procedures including many forms of surgery for placing objects or instruments at precise locations within a patient such as interventional radiology procedures and others.
In certain surgical procedures, there is a need for patient breath holding. Technological advances have enabled multi-detector row CT scanners to acquire high resolution scans over a region during a patient breath hold maneuver within a time period of less than ten seconds. Overall, this has enabled an increased number of patients to hold their breath for the short time period required to complete the scan to minimize motion artifacts. However, the increased Z-axis resolution of these CT scanners is not fully utilized when artifacts arising from respiratory motion are introduced into the image. As can be appreciated, patient respiration can change the position of tissues, targets, and critical structures during CT scanning. Simply, modern scanning apparatus are sensitive to patient motion.
In an attempt to minimize motion artifacts arising from respiration, patient breath holding training has been utilized. However, in spite of a training period, some patients (about 20%) have difficulty either initiating the breath hold when instructed to do so at the start of the scan or have difficulty holding their breath throughout the scan. Images acquired under those circumstances suffer from motion artifacts.
Another problem arising from procedures requiring breath holding is the relative inability to provide pre-operative and intra-operative breath hold congruency. More particularly, breath holds during the pre-operative planning phase and during the intra-operative phase of interventional treatments can vary leading to gross inaccuracy in instrument position or object placement within the patient.
Still further, another shortcoming of prior systems is the inability to completely integrate the patient imaging device/workstation with the patient breath holding detection devices. More particularly, data obtained from breath holding transducers currently available is not associated in any meaningful or useful way with the scanner/workstation displays, user controls, or with the acquired patient image data.
Overall, prior methods and apparatus do not automatically detect breath hold and do not have a means to automatically detect a deviation from a breath hold during a scan. Further, the prior systems are unable to record respiratory parameters together with imaging data such as CT data sets. They are further unable to record information with the imaging data relating to whether breath hold was maintained during a patient scan. Still further, the prior techniques are unable to stop the scanner when the breath hold is deviated and then restart the scanner after reestablishing the breath hold.
There is a need, therefore, to provide an automated, easy-to-use CT integrated respiratory monitoring device and method of using same. Preferably, the CT integrated respiratory monitoring device and method is useful in applications including breath holding during CT scanning, breath hold targeting for pre-operative and intra-operative interventional procedures, and for respiratory gating of imaging scanners.
Further, there is a need to provide a system for determining whether a patient is holding their breath at the start of an imaging scan. The system should be able to alert the technologist if the patient does not maintain the breath hold during the scan and identify images that were acquired while breath hold was not maintained. Preferably, the system provides an intuitive relaxing visual feedback to the patient to help them maintain their breath hold during the scan.
The present invention provides a new and improved CT scanner with integrated respiratory monitoring device and method of using same which overcomes the above-referenced problems and others.